Electric arc lamp



Dec. 22, 1931. j CROCKER 1,837,897

ELECTRI 0 ARC LAMP Filed Nov. 19, 1930 2 Sheets-Sheet 1 FIL I,

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ELECTRIC A Filed Nov. 19, 1930 C. T. CROCKER RC LAMP 2 Sheets$heet 2 Inventor- CLar-ence T. Cr'ocker',

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Patented Dec. 22, 1931 UNITED STATES,

PATENT OFFICE CLARENCE '1'. 030cm SOHENEO'I'ADY, NEW YORK, ASSIGNOB 1'0 GENERAL ELEC- TRIO (DKPANY, A. CORPORATION OF NEW YOBK meme Aachen Application filed November 19, 1880. Serial 1T0. 498,706.

The present invention relates to are lamps such as are used in connection with large searchlights, for example. In connection with such lamps it is desirable to have for the negative carbon a two-speed feed in each direction, that is, a high speed feed in each direction for establishing the are when the lamp is started and a slow-speed feed in'each direction for maintaining the are at the desired value during normal operation, the feeding being controlled by means responsive to an operatin condition of the arc, for example by means 0% the current flowing through the are or by the voltage across the arc.

The object of my invention is to provide an im roved construction and arrangement for e ecting the feeding of a negative arc lamp carbon after the manner referred to, and for a consideration of what I believe to be novel and my invention, attention is directed to the following specification and the claims appended thereto.

In the drawings, Fig. 1 is a side elevation of an arc lamp provided with a carbon feeda5 ing mechanism embodying my invention, the

casing enclosin the carbon feeding mechanism being bro en away to show the parts therein; Fig. 2 is a perspective view partly in section, of gearing forming a part of the so feeding mechanism, and Fig. 3 IS a circuit diagram.

Referring to the drawings, 1 indicates the positive carbon of the arc lamp carried by a supporting and feeding mechanism indicated generally by the reference numeral 2, the driving shaft for the mechanism being indicated at 3. The supporting and feeding mechanism 2 for the positive carbon lmay be of any suitable structure, a known structure which continuously rotates the arc and feeds it forward from time to time as required during the operation ofthe lamp being shown in the drawings. Its specific structure forms nopart of the present invention, and it is shown accordingly only in outline. The arrangement indicated is to be taken as indicating any suitable positive carbon. supporting and feeding mechanism.

4 indicates the negative carbon which is carried bya supporting and feeding mechfeeding mechanisms.

anism 5. The supporting and feeding mech anism comprises general y a pair of pivoted arms 6 which carry at oneend a pair of knurled feeding rolls (not shown) between which the carbon is located and which are adapted to be turned by means of gear wheels 7, the rolls being held in engagement with the carbon by a spr1ng 8 located between the arms 6. Meshing with gears 7 is a pair of worms 9 carried by a shaft 10 which in turn is connected by a connecting rod 11 to a. driving shaft 12. With this arrangement, when shaft 10 is turned in one direction gear wheels 7 are turned to feed the negative carbon forward and when the shaft is turned in the opposite direction gear wheels 7 are turned in a direction to move the carbon 4 backward, i. e., away from the end of carbon 1. The structure indicated is a known arrangement for feeding a negative carbon toward and away from the positive carbon and is shown only by way of example. In so far as the present invention is concerned, the essential thing is that whenshaft 10 is turned in one direction it moves negative carbon 4 toward the positive carbon and when turned in the other direction it moves negative carbon 4 away from the. ositive carbon, the rate of movement dependm 'on the rate of rotation of the shaft. "My invention relates particularly to an improved construction and arrangement for turning the shaft 10 whereby The mechanism for turning shaft 10 is 35 mounted in a casing 13 upgn which is located a) standard 14 for the car 11 supporting and Mounted in suitable bearing brackets 15in casing 13 is a shaft 16 which at its one end is provided with a worm wheel 17 with which meshes a worm 18 on the shaft of a driving motor 19. Driving motor 19 is connected preferably in parallel with the are so that it is subjected to voltage fluctuations depending upon the conditions of the arc. When the. lamp is operated the motor runs continuously, furnishing power for rotating the positive carbon 1 and for feeding the negative carbon 4.

For rotating the positive carbon, shaft 3 is 100 connected by a shaft 19* and suitable gearing to the motor driven shaft 16.

Mounted on shaft 16 are two sets of epicyclic gearing 20 and 21 which are alike in structure, one set being utilized for feeding the negative carbon forward and the other being utilized for feeding it backward. As these two sets of gearing are alike, only one, the gearing 20, will be described in detail. Referring particularly to Fig. 2, the gearing 20 comprises a double bevel gear wheel 22 which is keyed directly to shaft 16 so as to turn therewith and is cqnnected to gears 23 and 24 which are loosely inounted on shaft 16 by means of sets of planetary bevel gears 25 and 26 respectively, which in turn are rotatedly mounted on yokes 27 and 28 carried by shaft 16 and free to run thereon. Gears 23 and 24 mesh with gears 25 and 26' (see Fig. 1) fixed on a shaft 27 mounted in bearing brackets 15 and carrying on one end a bevel gear 29 which meshes with a bevel gear 30 on the lower end of shaft 12. Shaft 12 is carried in a bearing sleeve 31 attached to the cover of casing 13, the hub of bevel gear30 engaging the lower end of the bearing sleeve to take the upward thrust on the bevel gear 30. At 32 is a cap which is fastened to shaft- 12 and sets over the upper end of bearing sleeve 31 to prevent foreign particles from dropping into sleeve 31. It will be seen that gear wheels 23 and 25 are of sizes different from those of gear wheels 24 and 26 so that when shaft 27' is turned by the one set of gear wheels 23 and 25 it rotates at a lower speed than when it is turned by the other set of gear wheels 24 and 26". In other words, gear wheels 23 and 25 constitute the slow-speed feed for the negative carbon and gear wheels 24 and 26' constitute the highspeed feed for the negative carbon. Attached to yoke 27 is a notched ring 33 the teeth of which are adapted to be engaged by a pawl 34 mounted on an oscillating'shaft 35 pivoted in bearing brackets 15. Attached to yoke 28 is a notched ring 36 the teeth of which are adapted to be engaged by a pawl 37 similar to pawl 34 and similarlymounted on shaft 35. Pawls 34 and 37 are loosely mounted on shaft 35 between hubs 38 and 39, the pawls being free to turn on the shaft and being provided with tongues 40 which engage notches in hubs 39. Hubs 39 are provided with integral fingers 41 which are connected to "the outer ends of pawls 34 and 37 by springs 42. By this arrangement, when shaft 35 is turned in an anti-clockwise direction as viewed from the left-hand end in Fig. 2, fingers 41 are moved in a direction to turn pawls 34 and 37.

toward the toothed rings 33 and 36, the pawls being moved through the intermediary of the springs 42. Pawls 34 and 37 are set so that pawl 34 engages the notched ring 33 before the pawl 37 engages the notched ring 36. The first turning movement of shaft 35 brings pawl 34 into engagement with notched ring 33 and a further turning movement of shaft 35 brings pawl 37 also into engagement with notched ring 36, the spring 42-between finger 41 and pawl 34 yielding to permit of the additional turning movement of shaft As already stated, the gearing 21 is similar to the gearing 20. It differs therefrom only in that the pawls 43 and 44, corresponding to the pawls 34 and 37, are oppositely ar ranged with regard to shaft 35, being brought into engagement with the notched rings of gearing 21 when shaft 35 is moved in a clockwise direction as Viewed from the left-hand end in Fig. 1.

Shaft 35 is turned by a means responsive to an operating condition of the are so that as the operating condition varies the carbon 4 is fed forward or backward as required. To this end, there is connected to shaft 35 an arm 45, the free end of which is connected by a link 46 to a lever 47 pivoted at 48. The other end of lever 47 is connected to the plunger 49 of a solenoid 50. The winding of solenoid 50 may be connected either in series with the are or in parallel with the arc, depending on the control desired. In the present instance, it is shown diagrammatically in Fig. 3 as being connected in parallel with the are. With this arrangement, as the voltage across the arc increases and decreases the plunger is moved to turn shaft 35. On lever 47 is an adjustable weight 51 and also an adjustable spring 52 for counterbalancing the pull of the solenoid. Referring to Fig. 1, it will be seen that the lower end of spring 52 is connected to a pin 54 eccentrically mounted on the end of a shaft 54. Shaft 54 is mounted in a sleeve 55 and has on its outer end a knurled head 56 by means of which the shaft may be turned. The shaft is normally held from movement by interengaging projections 57 on the end of bearing 55 and the knurled head 56, the projections being biased into en gagement with each other by a spring 58 located between the end of bearing sleeve 55 and the eccentric mounting for pin 53. The spring 52 can be adjusted by pulling outward on knurled head 56 and turning the shaft 54, and it can be lockedin its adjusted position by releasing the knurled head, thereby permitting the projections 57 to again engage.

The operation is as follows:

When the circuit is first closed across the carbons, t e carbons being separated, full voltage is imposed on the coil 50 and plunger 49 is drawn downward turning shaft 35 to bring first the pawl34 into engagement with toothed ring 33 and then the pawl 37 into engagement with toothed ring 36. This locks the yokes 27 and 28 from turning and bevel gear 22 driven by motor 19 and shaft 16 drives gear wheels 23 and 24 through the bevel gears 25 and 26, the gears 25 and 26 turning on their spindles but, as already ill) stated, being held from traveling around the shaft 16 by the pawls 34 and 37 which lock the yokes 27 and 28. Gear wheel 24 drives gear wheel 26' and through the bevel gears 29 and 30 drives shaft 12 in a direction to feed forward the carbon 4 at the higher speed. At this time gear wheel 25' is driven by shaft 27 at a speed greater than that at which the gears 25 tend to drive gear wheel 23 and the action of the double differential results in turning yoke 27 slowly in a direction opposite to that in which shaft 16 is turning, the notched .ring 33 sliding under the pawl 34. With the higher speed drive effective, the negative carbon 4 is feed rapidly toward the positive carbon 1 and as soon as they almost touch the arc is established. When the arc is established the voltage on the coil 50 is reduced te a minimum, permitting the spring 52 toturn lever '47 and hence the shaft 35 in a direction to move pawls 34 and 37 from engagement with toothed rings 33 and 36 and to bring pawls 44 and 43 into engagement with the corresponding toothed rings of the gearing 21. This gearing then operates after the manner of the gearing 20 as just described to turnshaft 12 in the opposite direction at the higher speed and rapidly back the carbon 4 away from the carbon 1. As the carbon 4 is backed away from carbon 1 the voltage across the winding 50 increases, pulling the plunger 49 downward and lifting pawls 43 and 44 from engagement with the toothed rings. Spring 52 is adjusted so that when the desired voltage across the arc obtains, solenoid winding 50 holds plunger 49 in a position such that the pawls of both forward and reversing gear mechanisms 20 and 21 are disengaged. With no one of the toothed rings held from turning by its pawl, the 'y-okes 27 and 28 'of the gearing 20 and the corresponding yokes of the gearing 21 rotate about shaft 16, the gears 23 and 24 of the "gearing 20 and the corresponding gears of the gearing 21 being stationary. Now as the voltage increases or decreases slightly across the arc, solenoid 50 effects movement of .plunger 49 to bring the slow speed pawl 34 or 43 into engagement with its notched ring to effect a slow speed of the negative carbon 4 either toward or away from the positive carbon 1, as the case may be. The negative carbon feed is thus controlled by the lower speed gearing. If, during normal operation there occurs for some reason a substantial change in the voltage, the higher speed feed may be brought into operation, but this does not occur ordinarily. By adjusting calibrating spring 52 the mechanism can be set for the desired voltage across the arc.

By my invention, I have provided a twospeed feed in each direction which is relatively simple in structure and reliable in op- 65 eration and which is capable of operating in response to relatively small changes in the operating condition of the arc.

, In accordance with the provisions of the patent statutes, I have described the rinciple of operation of my invention, toget er with the apparatus-which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is: 1. The combination with an arc lamp having a carbon, of a two-speed feeding mechanism for the carbon comprising carbon feeding means, a driving shaft, a higher speed ,epicyclic gearing and a lower speed epicyclic gearing connecting the driving shaft to the feeding means, means for locking said epicycllc gearing to effect actuation of said feedlng means, and means responsive to an operating condition of the are for moving said locking means to locking positions.

2. The combination with an arc lamp having a carbon, of a two-speed feeding mechanism for the carbon comprising carbon feeding means, a driving shaft, 2. higher speed epicyclic gearing and a. lower speed epicyclic gearing connecting the driving shaft to the feeding means, pawls for locking said epicyclic bearings to effect actuation of said feeding means, and means responsive to an operating condition of the are for moving said pawls to locking positions.

3. The combination with an arc lamp having a carbon and a carbon feeding means, of a two-speed feeding mechanism for the carbon for moving it forward and back, each twospeed feeding mechanism comprising a driv- .ing shaft and a higher speed epicyclic gearing and a lower speed epicyclic gearing connecting the driving shaft to the feedin means, a second shaft, pawls carried by said second shaft-for locking the epicyclic gearings of each of said two-speed feeding mechanisms, the pawls for one of said feeding mechanisms becoming operative when said second shaft is turned in one direction and the pawls for the other feeding mechanism becoming operative when said second shaft is turned in the other direction, and means responsive to an operating condition of the are for turning said second shaft.

4. The combination with an arc lamp having a carbon and a carbon feeding means, of

a two-speedfeeding mechanism for the carmechanisms becoming operative when said second shaft is turned in one direction and the pawls for the other feeding mechanism becoming operative when said second shaft is turned in the other direction, and means comprising an electromagnet responsive to an operating condition of the are for turning said second shaft.

5. The combination with an arc lamp having a carbon, of a two-speed feeding mechanism for the carbon comprising carbon feeding means, a driving shaft, a higher speed and a lower speed epicyclic gearing on the a driving shaft, each having a driven gear, a

shaft having gears connected to said driven 7 gears and to the carbon feeding means, and

means responsive to an operating condition of the are for locking said epicyclic gearings.

6. The combination with an arc lamp having a carbon, of a two-speed feeding mechanism for the carbon comprising carbon feeding means, a driving shaft, a higher speed and a lower speed epicyclic gearing on the driving shaft each having a driven gear, a shaft having gears connected to said driven gears and to the carbon feeding means, and means responsive to an operating condition of the are for successively locking said epicyclic gearings.

In Witness whereof I have hereunto set my hand this 18th day of November, 1930.

CLARENCE T. CROCKER. 

